1. Field
Example embodiments may relate to semiconductor devices, for example, to non-volatile memory devices and/or methods of operating the same.
2. Description of the Related Art
Non-volatile memory devices, for example, flash memories, may be classified into NAND and NOR types. NAND and NOR type flash memory devices may have faster erase characteristics that utilize block erase characteristics. NAND and NOR type flash memory devices may have differing programming and/or reading methods and may have differing degrees of integration. Due to these differences, NAND and NOR type flash memory devices may not be used in similar applications.
Because random access may be easier in a NOR type flash memory device, NOR type flash memory devices may have faster read speeds and may more easily enable programs to be selectively stored therein. Because a channel hot electron injection (CHEI) method may be used in NOR type flash memory devices, operation voltage may be higher. It may be more difficult to reduce channel length to prevent or reduce punch-through due to higher operation voltage.
Further, NOR type flash memory devices may discharge electric charge in a previously-programmed cell through a bit line in a read operation. This discharging may be referred to as drain disturbance. NOR type flash memory devices may have an off-cell that may not be read in a read operation if an over-erased cell exists.